Ecofact
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Ecofact is Ireland's leading independent ecological and environmental consultancy. Posts by Dr. Will O'Connor.
Videos
Arterial drainage maintenance works on the River Morningstar at Athlacca, Co. Limerick. These works were completed by the Office of Public Works (OPW) during the period November 2025 to January 2026. I visited the site last week when the machines had already left the site. However, I have been provided with photos showing the works underway. Significant areas of riparian woodland have been removed, and alluvial woodland was also cleared from islands within the river. There is evidence of substantial silt mobilisation and in-stream disturbance. The riverbanks have been destabilised as a result of the removal of trees and other vegetation. Although silt fences are now present, they did not prevent fine sediment and wet soil from entering the channel during the work. Machines tracked instream during the salmonid close season. This damage will affect the river for years to come, and a permanent loss of riparian woodland has occurred. The removal of woodland set back from the riverbank extends well beyond what would be considered to be river maintenance works. The River Morningstar is an important salmonid nursery and spawning tributary of the River Maigue. The lower reaches of the River Maigue form part of the Lower River Shannon Special Area of Conservation (SAC) and the River Shannon and River Fergus Estuaries Special Protection Area (SPA). Works like these are completed under the Arterial Drainage Act (1945). They are supposed to protect against flooding, but in reality, they have the opposite effect. By draining water off farmland too quickly, river works like this increase flood risk in downstream urban areas. This work was completed to protect wet farmland in a natural floodplain. We do need flood mitigation measures - but they need to be effective, sustainable, and based on evidence. In most cases that means slowing the flow of water through natural flood management techniques and restoring floodplains and wetlands to absorb excess water rather than pushing it downstream. We need to reform the Arterial Drainage Act (1945) and recognise the vital role that floodplains, alluvial woodlands and wetlands play in flood management and mitigation. Instead of fighting against nature, we should be working with it to ensure communities are truly protected in the long term. A healthy, functioning river catchment benefits everyone - not just wildlife, but the people who live alongside it too.
Ecofact204,398 Aufrufe • vor 3 Monaten
The Blackwater fish kill - failures in investigating and protecting an EU Special Area of Conservation. We need to move beyond “fisheries” on our Natura 2000 rivers. This video shows the Blackwater River (Cork/Waterford) Special Area of Conservation (SAC) near Mallow, Co. Cork and features critically endangered Freshwater Pearl Mussels (Margaritifera margaritifera). I took these images during a survey I completed in August 2022 on the river. A major fish kill occurred in this stretch of river earlier this month. It is one of the largest fish kills ever recorded in Ireland, with media reports estimating that over 30 km of river were affected. Thousands of fish were killed, and other wildlife was also impacted. Yet to date no cause of the fish kill has been identified. All of the areas affected were within the SAC designated area. The Blackwater River (Cork/Waterford) SAC is designated for a range of aquatic species including Atlantic salmon (Salmo salar), Freshwater Pearl Mussel, White-clawed Crayfish (Austropotamobius pallipes), Sea Lamprey (Petromyzon marinus), Brook Lamprey (Lampetra planeri), River Lamprey (Lampetra fluviatilis), and Twaite Shad (Alosa fallax). It is also designated for Otter (Lutra lutra), and the river corridor supports a range of other protected species including birds such as Kingfisher (Alcedo atthis). Despite this, public reporting and official responses have focused almost exclusively on Brown Trout (Salmo trutta), a species that is not a qualifying interest of the SAC. The investigation was led by Inland Fisheries Ireland (IFI), but having a fisheries agency lead an investigation of a pollution event on a Natura 2000 river is itself part of the problem. The Blackwater is not only a fishery, but also a designated European site. For example, there are no “fisheries” for Freshwater Pearl Mussels, crayfish or lampreys in Ireland. International best practice sets out clearly how fish kills should be investigated. The first 24 hours are critical. Water samples must be collected above, within and below the affected reach, as well as from tributaries, with controls from unaffected areas. Dead and dying fish and invertebrates should be collected immediately for pathology and toxicology. Mortality must be quantified using standardised transects and statistical sampling, not casual tallies. On the Blackwater much of this did not happen. The 24-hour window for water sampling was lost, early speculation about natural causes was made without evidence, and mortality estimates were not carried out to scientific standards. There has been no reported assessment of impacts on Freshwater Pearl Mussels, lampreys or crayfish. There were reports of large numbers of “eels” being killed, and lampreys are often erroneously referred to as eels. Yet there does not seem to have been any formal investigation into how other non-fisheries species were affected. This failure raises a prima facie breach of Article 6(2) of the EU Habitats Directive, which requires Member States to avoid the deterioration of natural habitats and the disturbance of species for which SACs are designated. A pollution event of this magnitude, coupled with the absence of a scientifically robust investigation, amounts to both ecological harm and a failure of governance. An urgent independent review is now required into how fish kills are investigated in Ireland and how our Natura rivers are managed. Rivers such as the Blackwater cannot be treated as fisheries alone. They are legally protected ecosystems of European importance, and the State is obliged to manage and protect them as such.
Ecofact487,789 Aufrufe • vor 9 Monaten
Why are we building new weirs in our Natura 2000 rivers? This weir was built in 2017. It was constructed by Inland Fisheries Ireland (IFI) on the River Lackagh, Co. Donegal, to count salmon. It is located within the Cloghernagore Bog and Glenveagh National Park Special Area of Conservation (SAC). This SAC is designated for Atlantic Salmon, Freshwater Pearl Mussel, and Otter, yet no species-specific surveys for these species were carried out as part of the planning application. The Natura Impact Statement (NIS) submitted was notably lacking in detail, with generic and unworkable mitigation. There are records of Freshwater Pearl Mussels from this catchment yet the possible presence of this species downstream of this site was dismissed in the NIS as there were no previous records from the Lackagh River. It was not considered that this was because no previous surveys were ever done. Similarly Otters are almost certainly present, would be affected by a weir like this when foraging and commuting, yet again no formal surveys were completed. No ecological assessment was completed covering species that were not designated within the SAC. The NIS stated that “If any lamprey species, White-clawed Crayfish or Freshwater Pearl Mussel are detected during works, work should cease immediately and the National Parks and Wildlife Service should be contacted for further direction”. This was completely inadequate when no baseline surveys had been completed. A condition of planning was that IFI must approve all method statements for construction works. But IFI was the applicant, meaning there was no independent oversight of construction activities. When this weir was installed, no eel passes were provided, and the planning application did not even mention eels. I made a complaint to IFI, highlighting that eels are a critically endangered species and that this weir would block their migration. I received no response. However, when I visited the site last week, I noted that elver passes had recently been installed. But this is not a solution. This concrete fish migration barrier should never have been constructed in a Natura 2000 river. Elver passes are generally inefficient and quickly fall into disrepair. This has already happened at the few other sites in Ireland where elver passes were installed. This weir was funded under the “Salmon Conservation Fund.” However, counting salmon to set angling catch quotas has nothing to do with the conservation objectives of the SAC. The river was closed to angling because it was not meeting its conservation limit. The true purpose of the weir and fish counter was to gather data to support reopening the fishery and to resume exploitation of an endangered salmon population. However, since this weir was installed salmon runs, especially the early-running spring salmon for which this fishery was famous, have not improved. In fact, the runs have collapsed with <5% of the conservation limit now being reached. There is an inherent conflict between installing weirs to count salmon and maintaining passage for non-salmonid species. Eels have great difficulty passing barriers like this. A weir like this would completely block lamprey migration. In addition, most of this fish counting weirs do not produce accurate salmon counts. It is also likely that the weir affects salmon passage itself, particularly for early-running spring salmon trying to reach Glen Lough. The River Lackagh was historically the location where the first salmon of the year was often captured - sometimes on New Year’s Day. Spring salmon ran into Glen Lough from early January onwards. However, the ability of salmon to pass weirs is significantly influenced by water temperature. In early spring, low temperatures limit the physical ability of salmon to leap or ascend obstacles. Salmon cannot generally pass weirs easily until water temperatures reach 8–10°C, which is rarely achieved early in the year on this river. The likely impact of this weir on fish passage was not even considered in the NIS. There have been other damaging angling development projects in this catchment, carried out under the “National Strategy for Angling Development.” These include access roads, slipways, mooring pontoons, and other infrastructure for fishing access. While these developments may support tourism, they are not conservation actions. Instead, they contribute to disturbance of wildlife, increase biosecurity risks, and result in habitat loss within a Natura 2000 site. IFI is an angling development and management agency - and there is a place for that. But who is actually looking after our Natura 2000 rivers and protecting them from angling development pressures? Because there is a lot more to our rivers than just “fisheries”.
Ecofact440,255 Aufrufe • vor 10 Monaten
River Lampreys (Lampetra fluviatilis) at Annacotty Weir on the River Mulkear, Co. Limerick. These lampreys are on their upstream spawning migration, but they cannot get past this barrier. On suitable nights, they repeatedly attempt to find a way over the obstacle, and this can continue for months. The survivors will spawn in the spring downstream of the weir. Lampreys are poor swimmers and cannot jump like salmonids or climb like eels. As a result, even relatively small barriers in rivers can block their migration. River Lampreys are now absent from most of Ireland due to migration barriers in the lower reaches of rivers. Lampreys are fascinating creatures and are critical ecological components of aquatic ecosystems, contributing significantly to biodiversity. They evolved over 350 million years ago, before the dinosaurs. We need to put measures in place to conserve and protect these fascinating and valuable “living fossils”.
Ecofact181,030 Aufrufe • vor 4 Monaten
Ardnacrusha hydroelectric station yesterday evening, when ESB was abstracting almost 70% of the flow in the Lower River Shannon Special Area of Conservation (SAC). Water is diverted at Parteen Regulating Weir, and this abstraction affects over 15kms of internationally designated Natura 2000 river. ❌This is not “clean energy” and it is not “powering Ireland”, despite ESB’s claims. As seen in the video, much of the water taken from the SAC is simply being dumped through the spillway rather than used for hydroelectric generation. ⚠️This is a critical period for fish migration. Upstream migrating Atlantic salmon (Salmo salar) and River Lampreys (Lampetra fluviatilis) are following this diverted water into the tailrace, where they become trapped and are unlikely ever to spawn. Both species are Qualifying Interests of the SAC. ⚠️Downstream migrating critically endangered eels also follow the water into the unscreened turbines. Eels are also likely to get harmed if they pass though this 30m high spillway. They will also be exposed to 'gas supersaturation' in the tailrace and injured and disorientated fish are very vulnerable to predation. ⚠️The white screen on the station visible in the video is related to an ongoing multi-million-euro refurbishment, carried out entirely outside the planning system with no environmental assessment. Water management decisions are being made day-to-day and have varied significantly in recent years. ⚠️The water management ‘plan’ for this station is new, the refurbishment ‘project’ is ongoing, and both are having significant effects on the environment and the Lower River Shannon SAC. These impacts are cumulative with the impacts of the 1920s scheme and required Environmental Impact Assessment (EIA) and Appropriate Assessment (AA). ⚠️Salmon runs on the River Shannon have collapsed, and the entire SAC is being damaged by the unsustainable management of this hydroelectric scheme. The refurbishment was a major opportunity to implement mitigation measures to protect endangered fish, yet nothing was done. However, the key ecological problem on the Lower River Shannon is the over-abstraction of water. No fish pass could ever work with the situation shown in this video for example. ❌The current management of this hydroelectric scheme is incompatible with the legal requirements of the EU Habitats Directive and the Water Framework Directive. ✅What is needed is a formal SAC management plan for this Natura 2000 river, one that balances electricity generation with biodiversity, fisheries, flood risk management, and the needs of local communities.
Ecofact162,119 Aufrufe • vor 7 Monaten
The derelict elver pass on the River Fergus, Ennis, Co. Clare, this week. This elver pass was never maintained and quickly fell into disrepair. This is one of Inland Fisheries Ireland’s (IFI) fish counters. It is difficult to explain why IFI continues to maintain the fish counter here but has allowed the elver pass to fall into disrepair. The European eel is a critically endangered species, and fish passage problems at weirs and dams are among the key reasons for its decline. This fish pass was installed as part of a damaging flood scheme and was intended to help lampreys, but lampreys cannot use it either. This location is within the Lower River Shannon Special Area of Conservation.
Ecofact215,749 Aufrufe • vor 10 Monaten
This is a side of Limerick that many people don’t see. River Lampreys (Lampetra fluviatilis) stranded in the River Shannon in Limerick City yesterday afternoon. These lampreys were on their upstream spawning migration and became trapped when hydroelectric generation was abruptly stopped, coinciding with low tide. I returned the lampreys I found to the river, but when this happens, most are eaten by predators - especially gulls. This is the Lower River Shannon Special Area of Conservation (SAC), and the River Lamprey is a Qualifying Interest of this Natura 2000 site. We need sustainable water management at the dams on this river.
Ecofact128,154 Aufrufe • vor 1 Jahr
Atlantic Salmon (Salmo salar) and Brown Trout (Salmo trutta) attempting to pass Annacotty Weir on the River Mulkear, Co. Limerick, this afternoon. This ornamental weir, a legacy of a flood scheme, serves no purpose yet obstructs fish migration in the Lower River Shannon SAC.
Ecofact99,036 Aufrufe • vor 1 Jahr
Arterial drainage maintenance works have destroyed this tributary of Lough Derg. I first visited this site in April 1992, and hundreds of Brook Lampreys were present. It was the best site I ever found for this species. This was a ‘biodiversity hotspot’, with salmon, white-clawed crayfish, otters, and kingfishers all present. Whooper swans have used the adjoining fields. A few years ago, I saw a white-tailed eagle perched on a tree overlooking this river while I was surveying lampreys – but unfortunately, I only had my underwater camera with me. Part of this site lies within the Lough Derg (Shannon) Special Protection Area. The included clips of kingfishers were taken here in August 2020. The site is now unrecognisable, and there is not a single tree left on the bank where the kingfishers were nesting. The river channel here has been repeatedly degraded by arterial drainage maintenance works over the last four years. At this stage, it is unrecognisable from what it once was. OPW machines have been working on it again this year. Every time they return, a little less is left, and the banks are further destabilised, creating the requirement for even more maintenance works. Most of these works are politically driven. If a landowner is unhappy with their land getting a bit wet and contacts the local OPW office persistently enough, a machine will be sent out. The farm access roads here were also recently resurfaced, with further damage to the riverbank. The river is further affected by background pollution from agricultural activities. This riverbank is part of the Lough Derg Way, and some of the maintenance works appear to be linked to keeping the site ‘tidy’ for this. A footbridge was also recently installed over the watercourse – right at the site of the kingfisher nest. The planning application for this bridge included a 100+ page ‘Ecological Impact Assessment’ report, which missed everything important at the site. Most of the report is a vast compilation of largely irrelevant, ‘cut and paste’ information available online. The bridge forms part of a looped walkway along the SPA, yet only the bridge itself was “assessed” in the ecology report. All the important receptors were missed – including the kingfisher nest site. No Appropriate Assessment was carried out, despite the bridge increasing access for walkers and their dogs into the SPA. Incredibly, a few lampreys, salmon, and crayfish are still present in March 2025. Otters still visit occasionally. While I was on site this week, a kingfisher passed by. But these species have been pushed to the very edge and are likely to disappear from this area altogether. There is no suitable nesting habitat for kingfishers, and only a handful of lampreys remain. With no cover, the remaining lampreys, salmon, and crayfish will all be preyed on. Biodiversity in Ireland is under siege. But the works at this site are completely unnecessary. They achieve nothing in terms of flood protection. This is being done by the state because the landowner refuses to accept that their land will always be a bit wet – it lies beside a lake – and locals seem to want a ‘tidy’ walkway. The only thing missing here now is one of the signs about saving the bees.
Ecofact81,000 Aufrufe • vor 1 Jahr
Otter versus Salmon. An Otter (Lutra lutra) battles it out with an Atlantic salmon (Salmo salar) on the bank of the River Mulkear, Co. Limerick. The determination of the salmon to get back into the river, despite the odds, highlights the resilience of this species. Salmon only need half a chance, and we are not giving them that. The River Mulkear forms part of the Lower River Shannon SAC. Both Otter and Atlantic salmon are Qualifying Interests of this Natura 2000 site. Native natural predators are not a key factor in the decline of salmon populations; predation is a natural and ecologically important process that salmon have evolved with.
Ecofact25,323 Aufrufe • vor 5 Monaten
A major eel kill occurred on the Lower River Shannon on this day three years ago. Hundreds of critically endangered #eels were found dead downstream of the Ardnacrusha hydroelectric station following Storm Barra. This tragic event, both a wildlife crime and a fish kill, highlighted the urgent need for action. Yet, it was never properly investigated by Inland Fisheries Ireland, and no one was held accountable. The December 2021 eel kill should have marked the beginning of changes in how the Lower River Shannon is managed. Yet, nothing has changed, and this scheme is still being managed the same way it was in the 1930s. Yesterday, ESB Group was abstracting 96.7% of the flow in the Lower River Shannon SAC at the Parteen Regulating Weir. Migrating fish follow the water out of the SAC toward the unscreened turbines. The Habitats Directive, Water Framework Directive, and Eel Regulation have all come into force, yet nothing ever changes at this unsustainable hydroelectric scheme.
Ecofact39,618 Aufrufe • vor 1 Jahr
Current trail camera footage of a Pine Marten (Martes martes) at a site in north Co. Tipperary. The Irish name for the Pine Marten is 'Cat Crainn', meaning 'tree cat'. This native Irish species provides many ecological benefits, including helping to control the non-native invasive Grey Squirrel (Sciurus carolinensis). This benefits the native Red Squirrel (S. vulgaris), which is common at this location.
Ecofact10,477 Aufrufe • vor 4 Monaten
Atlantic Salmon (Salmo salar) attempting to pass Annacotty Weir on the River Mulkear, Co. Limerick, yesterday evening. Barriers like this place significant stress on salmon, draining their energy reserves, and often causing injuries. These fish still have a long journey upstream, with more obstacles to overcome, before reaching their spawning grounds. This is the Lower River Shannon SAC.
Ecofact25,479 Aufrufe • vor 1 Jahr
More footage of River lampreys (Lampetra fluviatilis) blocked at Annacotty weir last week. People have asked me why I don't put the camera down, net them, and move them over the weir—or why other locals don’t do this themselves with nets to ‘sort this out.’ I note that some netting did occur last week, but I have advised local people not to engage in this. Unfortunately, there may have also been instances of poaching. I’ve provided the following reasons why ad hoc netting is not recommended for this site: Reason 1: Netting without a license is illegal. Reason 2: Netting would need to be done every night, not just once, to address the issue. Reason 3: Without proper recording, the lampreys’ plight won’t be highlighted, which diminishes the case for a long-term solution. Reason 4: Unlawful, unplanned netting could encourage lamprey poaching for use as fishing bait. Reason 5: Improper handling could result in the lampreys being washed downstream again. Reason 6: Netting is inefficient and ineffective, as lampreys will scatter as soon as netting begins. Reason 7: Netting and handling can harm the lampreys. Reason 8: It’s dangerous to walk on a slippery weir. There’s a right way and a wrong way to address this issue. My original proposal for an interim solution involves using a trap. The lampreys are naturally drawn to the old sluice gate area of the weir, making it relatively easy to trap them here and move them upstream in a planned, managed way.
Ecofact24,369 Aufrufe • vor 1 Jahr
River Lampreys (Lampetra fluviatilis) at Annacotty Weir on the River Mulkear, Co. Limerick, this week. This barrier blocks lamprey migration in the lower reaches of this tributary of the River Shannon. These lampreys are on their upstream spawning migration but cannot get past this barrier. They repeatedly attempt to find a way over the obstacle on suitable nights, but there is no way upstream for them. This struggle continues for months, and eventually, the survivors spawn below the weir the following spring. However, this situation makes the population highly vulnerable, as they are confined to the lower 2 km of the river. The River Mulkear is designated as a Special Area of Conservation (SAC) for this species. It joins the River Shannon downstream of the hydroelectric scheme, which also blocks lamprey migration.
Ecofact20,789 Aufrufe • vor 1 Jahr
More footage of Atlantic Salmon (Salmo salar) attempting to pass Annacotty Weir this week. These fish are on their spawning migration but cannot find the entrance to the poorly designed fish pass at this location. They repeatedly attempt to pass this barrier, wasting valuable energy and risking injury. However, many of these fish will never reach their spawning grounds. The River Mulkear forms part of the Lower River Shannon SAC.
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River Lampreys (Lampetra fluviatilis) at Annacotty Weir on the River Mulkear, Co. Limerick, last night. These lampreys are on their upstream spawning migration, but they can't get past this barrier. They try repeatedly on suitable nights to find a way over this obstacle, and this continues for months. They won't spawn until next spring. The River Mulkear is designated as a Special Area of Conservation (SAC) for this species, yet this weir blocks access for lampreys to 98% of the catchment. Annacotty Weir serves no purpose. It is an ornamental structure—a legacy of a damaging flood scheme. The easiest way to rewild and restore our rivers is by removing barriers to fish migration.
Ecofact11,866 Aufrufe • vor 1 Jahr
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